The invention is related to a tobacco smoke filter material. In particular, it is related to a porous particulate material for selectively removing smoke acids and aldehydes. Hitherto, it has been proposed to disperse various materials, such as amines and/or amine salts, on conventional filter tows (see U.S. Pat. No. 3,410,282) to selectively remove smoke acids from tobacco smoke. Similarly, it has been proposed in U.S. Pat. No. 3,340,879 to treat conventional filter tow with a poly(alkyleneimine) to selectively remove smoke acids while allowing a major proportion of the flavorants to pass. Additionally, it has been proposed in U.S. Pat. No. 2,815,760 to adsorb specified amines on certain porous granules of unspecified pore diameter, surface area and pore volume to reduce volatile tobacco smoke components.
However, the aforesaid additives have not yielded satisfactory selective removal of such smoke phase components, as smoke aldehydes, particularly acetaldehyde and acrolein. As employed in this application, the term "filter material" refers to a porous particulate carrier impregnated with an additive of the invention. The term "additive" is applied to a moiety impregnated on the carrier with an affinity for volatile smoke acids and aldehydes.